Distorted TX audio on 6600

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  • Updated 3 months ago
I have distorted TX  audio 
I have listened in three different Radios and the TX audio sounds raspy  , I even recorded 
my test on the Flex to play back so not to get confused by listening to my audio at the same
time I was talking into mic , tried different microphones too.
Sounds like when your are using class C on a AMP instead of AB1 
Anyone have the problem  
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Ray Gustafson WB0HHM

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Posted 10 months ago

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Lou Dietrich

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Have you tried this?...

https://www.youtube.com/watch?v=CzT1qDKKySk

73

Lou N2TU
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Bill -VA3WTB

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Ray, there is a lot of information on this question. Even though you may have your mic audio levels peaking below the 0 mark, it is still very possible to have distorted audio, here is why.

The sliders on the EQ also work as gain controls, and can add gain to your overall audio. How ever this extra gain created from the EQ is not displayed on the mic audio meter.

In order to keep your audio smooth, some of us suggest to run the the EQ sliders below the 0 mark on the slider scale. This will still allow for needed adjustments to the EQ without adding to much audio boost to the mic audio circuit. Give this a try. And keep the low Freq levels down as well.
(Edited)
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Art - N4QNT

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Wondering if you have the Processor enabled? If so depending on the 8 band EQ levels at the 4, 6 and 8 K range, if those levels are above the plus 4 to 8 levels and the Processor is set at DX or DX plus the audio will be very distorted even if the Mic level is at 45 to 52..
(Edited)
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N8SDR

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Also check your microphone, if it does not require the bias voltage make sure it is OFF. Last night Art and I were helping a another op setup his 6K and a pr781- I know how they can sound once correctly setup, this one did not sound correct after making adjustments, turns out it had a slip on foam cover over the mic element, once it was removed it woke up and came to life- make sure when your adjusting nothing else is in front of mic until after you have it adjusted, then place your pop filter in place if needed.
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Bill -VA3WTB

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This correct Art. Setting the audio as I outline allows us to use the processor at any setting without distortion.
This is something I hope Can look at in the future.
In PSDR the EQ had an EQ meter to aid us in setting the EQ gain. That way we could set to max on the meter without adding distortion to the overall audio package.

The problem is with SSDR we have no meter or scale to use in setting the EQ in our 6000 radios. The mic audio meter only reflects the mic gain audio.
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KC2QMA_John

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Mic Gain is PRE (Before)  EQ and PROC.
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Art - N4QNT

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Hey John... and if I remember correctly even the Audio MON feature is PRE also..
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KC2QMA_John

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Correct.
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Bill -VA3WTB

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And that helps explain the  problem, after you set the mic gain to the best setting, we can pile on a lot more gain by setting the EQ sliders to high.
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KC2QMA_John

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One thing that works well for me is to set all EQ sliders at -5 then set your mic gain and PROC to NOR Or DX then just add a little EQ to your taste but try not to go over +2 with the EQ Sliders.
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Ray Gustafson WB0HHM

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Thanks for all the information , I will try some of the suggestions
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Gayle Lawson

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Any success with your audio problem?

Gayle K0FLY
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Ray Gustafson WB0HHM

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Not yet , but been busy with antenna work
I had a 6500 before the 6600 and I it always sounded so good
I keep thinking that the PA or driver is not linear ?
I going to measure current in transmit with no audio and post that
maybe someone can compare it to there 6600 , to get a idea of idling current
It won’t be true PA idling current, but may be worth checking.
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Gayle Lawson

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Ray:

Yes it sounds as if you got some hardware problems  I have  my original 6500 as well as a 6600.  Using the same mic  and profile on both radios my friends tell me there is a slight difference in an on the air A to B comparison.   If I just put one on the air they can' tell me which radio I'm using.  I use the compression meter as my drive indicator

I run my EQ sliders into the plus range, however, I set the mic gain so that there there is a small indication on the compression meter(maybe 5 db on peaks) with the processor in the normal position.  The mic input meter peak bar is usually is around -10 to -15 .  If you had good reports with the 6500 the 6600 should perform as well with the same mic and EQ settings.

Gayle K0FLY
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Ken - NM9P

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When adjusting your TX EQ, always cut what you don’t need FIRST (usually bass sliders). Then add what is missing (often some highs). Do this with PROC OFF. Then add processing.
Watch that you don’t slam the audio section with excessive bass, either with EQ of filter cutoff, or you can get distortion with the PROC even if your levels are below the red on the meter.

Ken - NM9P
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Ray Gustafson WB0HHM

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I have had 6600 off for a couple days and got it going today and it sounds good so far
I am leaving it on to see if it shows problem after on several hours

I have been leaving it on for several days before this.

Michael Aust send me information about Syncing Issue “Jitter in Internal 10 MHZ TCXO”
which sounds like it could be the issue
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Homer1952

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Lots of good comments here. 
Much like Ray WB0HHM, I've been struggling to get my 6400 to sound as good as my 6300.
No matter what I do, there is roughness & a sorta clipping sound to my SSB audio.
My Kenwood & Icom are free of this distortion.
I noticed a number of comments regarding EQ settings (vs mic gain) and to start low or cut & then increase EQ gain.
If this is an prudent approach, why aren't the preset EQ's that Flex provides, set up this way?

-Bob W8RMV

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Bill -VA3WTB

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With the information given here as you have read, you should have no problems achieving great sounding audio. The presets are only meant to be starting points, they do not address every ones voices. Most people who understand how the EQ works run their sliders no higher than +4 and mostly below 0. Keep in mind, all the sliders add gain to the mic input. The real problem slider are any at 1k and up. if you are distorting at all, roll them down till it clears up.
(Edited)
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Homer1952

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That means I must "understand" how to set the EQ on my 6300 but not my 6400.  6300 gets good reports & the 6400 gets bad reports with the same settings,mic, PS & connections.

I just ran a test on my 6400.  I put all equalization settings at -10 & had PROC at DX.   I then set the mic LEVEL so I could see the peak LEVEL indicator stay between -10 & 0.  The COMP indicator barely moved.  All tests are with MOX on into a dummy load.

Then I boosted the EQ to +10 for all frequencies, I saw the mic LEVEL did not change!!  But the COMP went off scale!!

So Flex is measuring Mic LEVEL before the EQ & COMP after the EQ.  This is a bit enlightening.

I now understand why some say to lower the EQ settings, especially true if you use COMP.
 
I just sold the 6300 so I could not test it. 

I have not recorded all the data, but it seems I hear a lot of bad 6400/6600's and no bad 6300/6500/6700's.  The circuits are supposed to be the same, save the modular architecture of the 6400/6600's.

I really like my 6400 & have tried everything I know to get it to sound good on SSB, but if I can't, it will go the way of the 6300.

I will investigate lowering the EQ across the board & try that tomorrow with a group I know that has a few Flex users in it.

- Bob W8RMV
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Bill -VA3WTB

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Homer, It will also depend on your mic, some mics have a boost in the mids or highs. so in that case the 1K and up would need more roll off then usual. And then their is the voice. I know for sure a 6400 can sound very good. I heard 4 of them last week and they all sounded great, but one of them was astounding, sweet mellow, rich. If you can't ever find good sound then I would think there is still something in your set up still causing it. I have a 6500 and can make it sound terrible if I set things wrong.
When you start to set up try this. Start with the 1K and up lower than it should be, so your audio sounds dull. Then slowly bring them up till you have detail in your voice. Instead of starting high and reducing them. You should find that sweet spot.